The document summarizes the exploration and settlement of North America by various indigenous groups and European colonizers. It describes how Mongols crossed the Bering Strait over 14,000 years ago and dispersed across North America. It then outlines the major indigenous settlements across North America, including the nomadic tribes of the Great Plains and Great Basin, and more agricultural societies in the Midwest, Northeast, and Atlantic seaboard. The document also summarizes the arrival of European colonizers like the Spanish, French, and British in the 15th-16th centuries and the impacts of colonization, including the introduction of new crops, animals, and diseases.